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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:dateCreated |
1992-6-5
|
| pubmed:abstractText |
Total syntheses of ganglioside GM1b (IV3NeuAcGgOse4Cer) and three of its positional analogs are described. Methyl O-(methyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D- glycero-alpha-D-galacto-2-nonulopyranosylonate)- (2----3)-2,4,6-tri-O-benzoyl-1-thio-beta-D-galactopyranoside (7) and methyl O-(methyl 5- acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero-alpha-D-galacto-2 -nonulopyranosylonate)-(2----6)-2,4-di-O-benzoyl-3-O-benzyl-1-thio - beta-D-galactopyranoside (8) were the key glycosyl donors, prepared according to our reported methods. Coupling of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-alpha-D-galactopyranosyl bromide and 2-(trimethylsilyl)ethyl O-(2,3,6-tri-O-benzyl-beta-D- galactopyranosyl)-(1----4)-2,3,6-tri-O-benzyl-beta-D-glucopyranoside gave a trisaccharide, which after removal of O-acetyl and phthaloyl groups was converted separately, by benzylidenation and dibutyltin oxide-mediated selective benzylation, into two glycosyl acceptors. These were suitable respectively for C-3 and C-6 glycosylation reactions, promoted by dimethyl(methylthio)sulfonium triflate (DMTST), with the donors 7 and 8. The four possible coupling reactions gave the corresponding four pentasaccharide derivatives in high yields, and these were transformed into their respective alpha-trichloroacetimidates. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with the alpha-trichloroacetimidates gave the corresponding beta-glycosides, which on channeling through selective reduction of the azido group, coupling of the thus formed amino group with octadecanoic acid, O-deacetylation, and saponification of the methyl ester group, gave the title compounds.
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| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Nov
|
| pubmed:issn |
0008-6215
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
11
|
| pubmed:volume |
220
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
127-43
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1991
|
| pubmed:articleTitle |
Regio- and stereo-selective synthesis of ganglioside GM1b and some positional analogs.
|
| pubmed:affiliation |
Department of Applied Bioorganic Chemistry, Gifu University, Japan.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|